1. Field of the Invention
The present invention relates to a lens barrel of a camera and a lens unit.
2. Description of the Related Art
Conventionally, a lens barrel of a camera capable of switching between an auto focus operation and a manual focus operation in a non-manipulating manner is known, and is disclosed, for example, in Japanese Patent Application Laid-open No. H6-11636. The lens barrel disclosed in Japanese Patent Application Laid-open No. H6-11636 includes a fixed barrel, a movable lens holding member (lens holder) that holds a movable lens group and is movably disposed on the fixed barrel, a rotating member that holds rolling rollers rolling in a state of being sandwiched with constant urging force, and is disposed to be rotatable with respect to the fixed barrel, a single rod-like lens drive operation member that connects the movable lens holding member and the rotating member, and drives the movable lens holding member. In this lens barrel, a cam screw provided on the movable lens holding member is inserted into a cutout provided on the rotating member through a cam groove provided on the fixed barrel. In such a lens barrel, the rotating member is rotationally driven by actuation of a motor, or a manual operation, the rotating member operates in response to the actuation of the motor or the manual operation, and at the time of this movement, the cam screw inserted into the cutout is pressed to move through the cam groove. Due to this, it is possible to perform a drive operation of the movable lens holding member holding the movable lens group, in an axial direction with respect to the fixed barrel.
The lens barrel disclosed in Japanese Patent Application Laid-open No. H6-11636 transmits rotational force of the rotating member to the movable lens holding member with the single rod-like lens drive operation member, and hence force other than force in a rotational direction largely acts on the rotating member. Therefore, a pressed state of the rolling rollers rolling in the state of being sandwiched with the constant urging force becomes unstable, and transmission efficiency is lowered. A drive loss in driving the movable lens group is large, and great force is required in order to perform the drive operation, with respect to the fixed barrel, of the movable lens holding member holding the movable lens group.